I somewhat agree. I tried a K&N air filter on my cars, expecting more air flow. But that didn't happen. Seems that the sensors recognize the amount of air passing through the air filter will alter the amount of fuel being used and change the dynamics. No improvement in performance when engine speed is between 500 and 4,000 rpm. It might help when over 5,000rpm, but I seldom do that.

The real problem with K&N is when it is time for cleaning. All of the oil and dirt must be washed out and the filter re-oiled. Doing this usually results in oil being applied too heavily or unevenly, and the oil vapors then attach to the sensor, causing it to become dirty and inefficient.

A dry paper filter, changed annually, is the cheapest and best way to take care of your engine. Except in an emergency, like driving the length of Baja where you should take out the filter and bang the dust out of the filter (no can do with an oiled filter), the paper filter actually lets enough clean air pass to satisfy most drivers.

The MAF and ETM both get dirty with age + miles. There is no scheduled maintenance for either, but there should be. The ETM gets dirty because of the crankcase ventilation system which drives oil fumes through the throttle. This is less of a bother with synthetic oil, but still exists.

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Keeping it running is better than buying new